A variety of flavorants have been developed and proposed for incorporation into tobacco products. Illustrative of such tobacco flavorants are those described in U.S. Pat. Nos. 3,580,259; 3,625,224; 3,722,516; 3,750,674; 3,879,425; 3,881,025; 3,884,247; 3,890,981; 3,914,451; 3,915,175; 3,920,027; 3,924,644; 3,937,228; 3,943,943; 3,586,387; 3,379,754; and the like.
J. C. Leffingwell et al "Tobacco Flavoring For Smoking Products" (R. J. Reynolds publication, 1972) recites a listing of desirable flavorants for smoking compositions, which include phenols, terpenols and lactones such as guaiacol, 1-undecanol and 5-dodecalactone.
The high degree of volatility and ease of sublimation of flavorant additives in tobacco products have presented problems in the manufacturing operations, and have resulted in a decreased shelf-life of the products due to losses of flavorant by evaporation on storage.
Recent developments have involved incorporating a low volatility organic additive to a smoking composition, which under smoking conditions is pyrolyzed into one or more fragments that function to improve the taste and character of mainstream tobacco smoke, and in some cases a consequential improvement of sidestream smoke aroma.
U.S. Pat. No. 3,312,226 describes smoking tobacco compositions which contain an ester additive such as l-menthyl linalool carbonate. Under smoking conditions pyrolysis of the carbonate ester releases menthol which flavors the mainstream smoke.
U.S. Pat. Nos. 3,332,428 and 3,419,543 describe smoking tobacco compositions which contain a menthyl carbonate ester of a glycol or saccharide, which under smoking conditions decomposes to release free menthol into the mainstream smoke. U.S. Pat. No. 3,499,452 discloses similar smoking tobacco compositions in which a carbonate ester additive releases flavorant volatiles other than menthol.
U.S. Pat. Nos. 4,119,106; 4,171,702; 4,177,339; and 4,212,310 describe other oligomeric and polymeric carbonate ester derivatives which as constituents of smoking compositions are stable and non-volatile under storage conditions, and are adapted to release pyrolysis products under smoking conditions that improve the taste and aroma of the smoke.
U.S. Pat. Nos. 4,036,237; 4,141,906; and 4,178,458 describe .beta.-hydroxyesters which as additives in smoking compositions pyrolyze into volatile aldehyde and ester flavorants under smoking conditions.
U.S. Pat. Nos. 4,473,085 and 4,607,118 describe .beta.-hydroxyesters which as additives in smoking compositions pyrolyze into volatile ketone and ester flavorants under smoking conditions.
Of general interest with respect to the present invention is the proposed utilization of carboxylate metal salts as additives in the combustible filler of smoking compositions to modify the composition and properties of generated smoke, such as described in U.S. Pat. Nos. 3,924,642 and 4,489,739.
There is continuing research effort to develop low delivery smoking compositions which generate mainstream smoke with enhanced taste and sidestream smoke with a pleasant aroma under smoking conditions.
Accordingly, it is an object of this invention to provide smoking compositions having incorporated therein a flavorant-release component which is characterized by lack of mobility and/or volatility at ambient temperature.
It is another object of this invention to provide cigarette smoking products having a paper wrapper which has incorporated therein a flavorant-release additive which under normal smoking conditions imparts improved aroma to sidestream smoke.
It is a further object of this invention to provide novel acetals and ketals of tartrate salt compounds which are adapted to be incorporated into cigarette filler and/or paper wrapper components, and which under normal smoking conditions release a volatile aldehyde or ketone flavorant into cigarette smoke.
Other objects and advantages of the present invention shall become apparent from the following description and examples.